The proposed research will investigate the structure and function of surface and intracellular membranes as they relate to excitability properties, ionic permeabilities, active transport, and the initiation of muscle contraction. In nerve and muscle, the surface membrane components which regulate specific transport functions will be investigated and attempts made at identifying these specific regulatory components. In these studies, artificial lipid bilayers will be utilized to incorporate components isolated from cell membranes and to analyze their function. In muscle, the interaction between the membranes of the cell surface, the tubular structures, and the sarcoplasmic reticulum will also be investigated in their relation to the initiation of muscle contraction.